1. Field of the Invention
This invention relates to a flat circuit device, which is applied for an electric wiring in a car or in an electronic equipment and a method of manufacturing the flat circuit device, especially to the flat circuit device which can be connected with a connector without another special terminals and the method of manufacturing the flat circuit device.
2. Description of the Related Art
A flat circuit device is used for an electric wiring in a car or electronic equipment, and has an electromagnetic shield type without a shield layer, which is disclosed by J.P.A. H5-120928.
In the flat circuit device, there are a flat device 54 being formed to join a first insulating film 51 having a first flat conductor 50 on one side surface thereof and a second insulating film 53 having a second flat conductor 52 on one side surface thereof with an adhesive as shown in FIGS. 17, 18, and a flat circuit device 59 being formed to fold one sheet of insulating film 55, having separately a first flat conductor 56 and a second flat conductor 57 at a predetermined distance on one side surface thereof, on a folding axis 58 between the flat conductors 56, 57 and join the other surface of the film together with a adhesive as shown in FIGS. 19, 20. The first and second flat conductors 50, 52, 56, 57 are formed into a meandering curve like a sine wave and are located symmetrically on practically one axial line when viewing from a direction perpendicular to surfaces of the flat circuit devices 54, 59.
Thereby, when a magnetic flux is given in a direction perpendicular to a surface of the flat circuit device 54 or 59 (a direction of thickness), noise generation is suppressed. When a magnetic flux is given in a direction of thickness of the flat circuit device 54 or 59, induced voltages V11 and V12 are generated oppositely in each adjacent area of the first flat conductor 50 or 56 and the second flat conductor 52 or 57 so that the induced voltages V11 and V12 in each adjacent area of the respective flat conductors 50, 52, 56, 57 cancel each other, and then a large induced voltage in total as a noise is not generated. On the other hand, when currents flow oppositely in the first flat conductor 50 or 56 and in the second flat conductor 52 or 57, magnetic flux is generated in opposite directions in each adjacent area so that the magnetic fluxes generated in adjacent areas cancel each other to suppress noise generation.
The flat circuit device mentioned above is formed to provide a flat insulator between the first flat conductor and the second flat conductor so that the flat circuit can not connected with a connector without a connecting terminal to be joined with an end of the flat conductors. Thus, another terminals are required and then when terminals are forgotten to be joined or lost, the flat circuit device cannot be connected with a connector.
To overcome the above drawback of prior art, one object of this invention is to provide a flat circuit device which can be connected to a connector without another terminals and the method of manufacturing the flat circuit device.
In order to attain the objects, a flat circuit device according to this invention includes a first conductor, a second conductor, and an insulator being provided between the first conductor and the second conductor, wherein the first conductor and the second conductor are located to form an area being surrounded by the first conductor and the second conductor when viewing from a direction perpendicular to a surface of the insulator, wherein the insulator includes a bent portion and a laminated portion of a first insulator and a second insulator forming the bent portion, whereby a side end of the bent portion of the first conductor extends straightly along a curved surface of the bent portion, whereby a side end of the second conductor at the bent portion extends straightly along a curved surface of the bent portion.
Structured as mentioned above, an end portion of the first bent portion and an end portion of the second bent portion are formed straightly along respective outer surfaces of the bent portions so that the bent portions can perform as connecting terminals to be connected to the other connecting terminals. Therefore, the flat circuit device can be connected to a connector without another terminals.
Preferably, the insulator is laminated by folding a flexible flat strip-like insulator and a pressing rib having a contact surface with U-shape in cross section to be contacted to the insulator is provided in the bent portion.
Providing the pressing rib in the bent portion as mentioned above, when the bent portion is contacted to the connecting terminals, the bent portion is not deformed so that the first and second conductors are contacted to the connecting terminals in good condition to ensure electrical connection.
Preferably, the insulator is laminated with a first insulator and a second insulator to fold a flexible flat insulator, which is provided in parallel with two strip-like portions of the first insulator and the second insulator to be connected by two portions of a first joining portion and a second joining portion, curvedly at the joining portions, and the first conductor is provided on the first insulator along lengthwise thereof to form one end portion of the first conductor extending straightly at the first joining portion and the other end portion of the first conductor extending straightly at the second joining portion, and the second conductor is provided on the second insulator along lengthwise thereof to form one end portion of the second conductor extending straightly at the first joining portion and the other end portion of the second conductor extending straightly at the second joining portion.
Structured as mentioned above, respective both end portions of the first conductor extend straightly at the first joining portion and the second joining portion along surfaces of the joining portions and respective both end portions of the second conductor extend straightly at the first joining portion and the second joining portion along surfaces of the joining portions so that the first joining portion and the second joining portion perform respectively connecting terminals to be connectable to other connector terminals. Therefore, the flat circuit device can be connected to a connector without another terminals at the both end portions of the first and the second conductors.
Preferably, the first and second conductors are formed into meandering curves symmetrical on respective base lines which are located on practically the same straight line when viewed from a direction perpendicular to a surface of the insulator, and the first and the second insulators are provided respectively with insulating pieces for surrounding alternately turning portions of the first and the second conductors forming areas surrounded by the first and the second conductors, and are provided respectively with slits for inserting the insulating pieces therethrough to place partial areas of the first and the second conductors respectively on each surface opposite to the laminated surface of the other insulator.
Structuring as mentioned above, an area surrounded by the first and the second conductors is formed between two cross points of the conductors when viewing from a direction of width of the flat circuit device so that, even if magnetic flux in a direction of the width is provided, induced voltages are generated oppositely in each adjacent area of the first conductor and the second conductor and then, the induced voltages in each area of the respective conductors cancel each other and generating a noise is depressed. When currents flow oppositely in the first conductor and in the second conductor and magnetic flux of directions of thickness and width of the flat circuit device is generated in each adjacent area, the magnetic fluxes flow alternately in opposite directions in order of directions of thickness and width so that the magnetic fluxes cancel each other to suppress noise generation. Thus, the induced voltage by magnetic fluxes in directions of thickness and width of the flat circuit device are canceled to depress generating a noise, and shield effect of the flat circuit device is enhanced.
Preferably, the first conductor is formed into a wave-shape meandering curve and the second conductor is formed into a curve having a smaller amplitude than that of the first conductor on a base line to be a straight line being located on practically the same base line of the first conductor when viewing from a direction perpendicular to the surface of the insulator to place cross points of the first and the second conductor on the straight line, and the laminated two insulators is curved or bent to place the base line of the first conductor on top of curved form when viewing from a direction perpendicular to the surface of the insulator and to place the base line of the second conductor on practically the same straight line as the base line of the first conductor being formed into a wave-shape meandering curve when viewed from a direction of width of the insulator.
Structured as mentioned above, an area surrounded by the first and the second conductors is formed between two cross points of the conductors when viewing from a direction of width of the flat circuit device so that, even if magnetic flux in a direction of the width is provided, induced voltages are generated oppositely in each adjacent area of the first conductor and the second conductor and then, the induced voltages in each area of the respective conductors cancel each other and generating a noise is depressed. When currents flow oppositely in the first conductor and in the second conductor and magnetic flux of directions of thickness and width of the flat circuit device is generated in each adjacent area, the magnetic fluxes flow alternately in opposite directions in order of directions of thickness and width so that the magnetic fluxes cancel each other to depress noise generation. Thus, the induced voltage by magnetic fluxes in directions of thickness and width of the flat circuit device are canceled to suppress noise generation and the shield effect of the flat circuit device is enhanced.
Preferably, a pressing rib having a contact surface with U-shape in cross section to be contacted to the insulator is provided in the curved joining portion.
Providing the pressing rib in the joining portion as mentioned above, when the curved joining portion is contacted to the connecting terminals, the joining portion is not deformed so that the first and second conductors are contacted to the connecting terminals in good condition to ensure electrical connection.
Preferably, the insulator has a slit portion along a bent curve between the first conductor and the second conductor on a bent portion of the insulator and the pressing rib has a center-adjust projecting piece to be inserted into the slit portion on the contact surface of the pressing rib.
Structured as mentioned above, the center-adjust projecting piece performs a partition to part the first conductor and the second conductor in the curved portion so that, when the flat circuit device is contacted to a connecting terminal, contact failure of the conductor caused by shifting the terminal widthwise in the insulator does not exist and the terminals can be contacted securely to the first conductor and the second conductor.
Preferably, the insulator has positioning holes, at the both end portions thereof, to be located on the same axis when the insulator is laminated.
Structured as mentioned above, to insert a positioning pin into the positioning holes being provided in the vicinity of the both end portions (a first and a second end portions) of the insulator when laminating the insulator, relative position of the first and the second insulators is always maintained in the same position so that the first and the second conductors can be positioned precisely and easily and then positioning accuracy and manufacturability of the flat circuit device are enhanced.
A method of manufacturing a flat circuit device comprises steps of providing a first conductor being formed on one side surface of a flexible flat strip-like insulator into a straight line extending along lengthwise the flexible flat strip-like insulator at central area of the insulator and into a wave-shape meandering curve from the straight line to one end of the insulator along the surface of the insulator on a base line of an axis extending along lengthwise the insulator, providing a second conductor being formed on the one side surface of the insulator into a straight line parallel with a predetermined distance to the first conductor at central area of the insulator and into a wave-shape meandering curve with practically the same phase of the first conductor on a base line of an axis being located on the base line of the first conductor from the straight line to one end of the insulator, coating adhesive on the other side surface of the flexible flat insulator from the center thereof to any of ends thereof, folding the flexible flat insulator curvedly at a center portion thereof to make the other surface with coated adhesive inside, laminating the both ends of the flexible flat insulator, clamping the both ends of the insulator with a pair of spring ribs for bonding the both ends by pressure, and sliding the pair of spring ribs from the both ends toward the center portion of the insulator for bonding the insulator.
Thus, bonding the insulator gradually from the both ends to the center portion thereof with pressure by the pair of spring ribs, the insulator can be bonded without air bubbles between the insulator so that the flat circuit device can be manufactured easily and accurately.
Preferably, a positioning pin is inserted into positioning holes to be located coaxially and provided respectively at the both ends of the laminated insulator.
Structured as mentioned above, when bonding the insulator, relative position of the insulator to be bonded is always maintained in the same position so that the first and the second conductors can be positioned precisely and easily and then positioning accuracy and manufacturability of the flat circuit device are enhanced.
Preferably, providing a jig body of a bonding jig having a contact surface with U-shape in cross section to contact with the insulator between the insulator, making the jig body support the pair of spring ribs by means of a removable supporting member, sliding the pair of spring ribs from the both ends to the center portion of the insulator, abutting the jig body on an inner surface of the bent portion of the insulator, and removing the pair of spring ribs together with the supporting member from the jig body, thereby, the jig body is used for a pressing rib.
Structured as mentioned above, the jig body for bonding the insulator can be used for the pressing rib so that another pressing rib is not required and an operation or an equipment to place the another pressing rib in the bent portion of the insulator is not required.
Preferably, the jig body has a bond-protect rib on one contact surface, corresponding to the surface with coated adhesive of the insulator, of two contact surfaces thereof extending in parallel, along lengthwise the one contact surface for preventing the insulator from bonding to the one contact surface.
Structured as mentioned above, the insulator can be bonded without bonding to the jig body.
The above and other objects and features of this invention will become more apparent from the following description taken in conjunction with the accompanying drawings.